Xavier Lozano

Lead Android Engineer ad0l5v@r.postjobfree.com 720-***-****

Profile Summary

•Nearly 11 years’ experience in Android development.

•7 apps published to Google Play Store.

•Experienced developing Android/Mobile apps on MVVM and MVP architectural models.

•Experience working with Kotlin, Java, JavaScript, jQuery building multiple solutions and design patterns.

•Proven effective working on Agile teams applying Scrum project execution principles to complete software development lifecycle (SDLC) projects involving the design, development, testing, and deployment of Android mobile apps to the Google Play Store.

•Experienced consuming backend RESTful web services with JSON and XML-based responses.

•Skilled integrating Android back-end services using Rx Java, Retrofit, and Kotlin Coroutines and implemented system service solutions with WorkManager.

•Comfortable with source control software programs such as GIT, GitHub, GitLab, Bit Bucket, etc.

•Fully versed driving development and deploy stages with tools like Gitlab, Github Actions, FastLane and Jenkins.

•Great expertise building appealing UI/UX designs that follows Material Design v2 and v3.

•Experienced implementing application data persistence using DataStore, Room DB, SQLite,Encyrpted Shared Preferences, Shared Preferences, and External and Internal storage.

•Demonstrated skill applying dependency injection using tools such as Koin, Dagger2 and Hilt.

•Demonstrated sill applying threading with tools such as Rx Java, Rx Android, Kotlin Coroutines, Intent Services, Handler, AsyncTask, Threads, and Loopers and Loaders, HandlerThread, Executors and Kotlin Flow.

•Experienced with design patterns Abstract Factory, Façade, Builder and Singleton.

•Knowledgeable and skilled utilizing Test Driven Development (TDD) and Continuous Integration for test automation to ensure high quality and easy-to-deploy app updates.

•Skilled with testing/debugging tools such as jUnit, Leak Canary, Espresso, and Dalvik Debug Monitor Server (DDMS).

•Expertise applying and debugging web services, including JSON, XML, and GSON utilizing tools like PostMan and Charles Proxy.

•Combine hard technical skills in Android development/deployment with soft skills to serve as valuable Agile/Scrum team member on mobile projects covering multiple industries.

•Contribute to story estimation, Sprint Planning meetings, Sprint Retrospectives, and Backlog grooming and Daily Stand-ups.

•Communicate effectively with stakeholders to manage expectations, gather business requirements, and translate them into technical specification documents and solutions.

Technical Skills

•Programming Languages:

Kotlin, Java, JavaScript, jQuery, C++, Groovy

•Architecture Design Patterns:

MVVM, MVP, MVC

•Design Patterns and Practices:

Adapter, Factory, Builder, Singleton, Extension Function, Handler

•Databases/Languages: SQLite, Room Database, Firebase Realtime DB, MySQL, MS SQL, GraphQL

•Dependency Injection:

Dagger2, Android Hilt, Koin

•Debug/Testing/Performance Frameworks:

Junit, Espresso, Hugo, Robotium, Mockito, LeakCanary, Doze Mode, Timber, Bluetooth BLE, Charles Proxy, MockK, Postman

•Version Control:

Git, GitHub, GitLab, TFS

•Project Management:

JIRA, Sketch, Trello

•Software Development Methodologies:

Agile, Scrum

•UI/UX:

Material Design, Material Dialogs, Calligraphy, ExoPlayer, VideoView, Chromecast, Push Notifications

•Networking/Web Services:

REST, JSON, Retrofit, GSON, OkHTTP, WebAPI2, Volley, GraphQL

•CI/CD:

Circle-CI, Jenkins, NDK, FastLane, GitLab

•Security:

AES/Cipher, Spongy Castle, Android Keystore

•Messaging:

Urban Airship, Google Cloud Messaging, FCM

•Payment Processing:

BrainTree SDK

•Analytics:

Adobe Analytics, Google Analytics, Mixpanel

•Libraries: MockK

•Other:

JetPack, IoT, Services, Zeplin

Work Experience

Lead Android Engineer May 2022 – Current

Charter Communications, Denver, CO

Headless app mainly focused on network connectivity (Wi-Fi and LTE/5G) and Background Services. It manages networking, e-Sim, and user analytics. This involved the use of Java, Kotlin, Job Scheduler, Work Manager, Coroutines, SQL, Firebase, JUnit, Mockito, Robo-electric.

•Designing and developing high-quality Android applications for Charter Communications' products and services which involves understanding of business requirements, translating them into technical specifications, and implementing robust and efficient solutions.

•Writing clean, maintainable, and efficient code in Java and Kotlin and various libraries and frameworks to implement new features and enhancements for Android applications.

•Designed the app in MVVM (Model View ViewModel) pattern.

•Conducting unit testing and debugging to ensure the quality and reliability of the codebase.

•Developed functionality in the headless app running on the device's firmware.

•Reviewed JSON payloads loaded into firebase and the database for registered devices.

•Worked with Jetpack components like ViewModel, RoomDB, Databinding, Navigation and Datastore.

•Used LiveData and Flows along with Coroutines for Data Flow from Repository to View.

•Applied features using Geofencing as well as fused location and configured analytics fields to properly identify the latest location in the client device.

•Used Robo-electric, Mockito, and JUnit for testing, increase the code coverage in the overall project to 85%.

•Facilitate deployment and developed Python scripts to automate QA testing to simplify deployment across multiple libraries in the project.

•Implemented security with SafetyNet Attestation, Endpoints with Nonce & Token Security and SSL Pinning with Pinner on OkHTTP.

•Optimizing the performance on the app by profiling the CPU and memory usage, with Profiler and Perfetto.

•Conducting regular code reviews, identifying bugs, and fixing issues to maintain the stability and reliability of the Android applications.

•Established and enforced best practices for C++ integration within the Android development team, including rigorous code reviews and knowledge sharing sessions.

•Ensured cross-platform compatibility by incorporating C++ components, allowing for code reuse across different platforms while maintaining consistent functionality.

•Successfully refactored and enhanced legacy code components within our Android apps using the NDK.

•Remained updated with the latest NDK updates, trends, and best practices. Actively sought opportunities to apply new knowledge to our Android app development processes, ensuring that we remained at the forefront of technology.

•Identifying and addressing performance bottlenecks and memory leaks in Android applications. Optimizing app performance to deliver smooth user experiences and efficient resource utilization.

•Creating and maintaining technical documentation, including design documents, API specifications, and user guides.

•Providing technical support to internal teams and external customers to address their Android-related queries and issues.

•Performing troubleshooting and providing timely resolutions for production incidents.

•Participating in Agile development processes, including sprint planning, stand-ups, and retrospectives. Actively contributing to process improvement initiatives and sharing knowledge within the team to enhance productivity and efficiency.

•Spearheaded the strategic integration of GraphQL into our Android app development process, replacing traditional REST APIs. This transition enabled a more efficient and customizable data retrieval process, which significantly improved our app's performance and responsiveness.

•Staying updated with the latest trends, best practices, and emerging technologies in Android development. Evaluating new tools, libraries, and frameworks to improve the development process and enhance the functionality of Android applications.

•Collaborating with cross-functional teams including product managers, designers, backend developers, and QA engineers to gather requirements, define technical solutions, and deliver high-quality software products.

•Communicating effectively with team members and stakeholders to ensure smooth project execution.

Senior Android App Engineer January 2020 – May 2022

Krispy Kreme, Chicago, IL

https://play.google.com/store/apps/details?id=com.krispykreme.HotLights HYPERLINK "https://play.google.com/store/apps/details?id=com.krispykreme.HotLights&hl=en_CA&gl=US"& HYPERLINK "https://play.google.com/store/apps/details?id=com.krispykreme.HotLights&hl=en_CA&gl=US"hl=en_CA HYPERLINK "https://play.google.com/store/apps/details?id=com.krispykreme.HotLights&hl=en_CA&gl=US"& HYPERLINK "https://play.google.com/store/apps/details?id=com.krispykreme.HotLights&hl=en_CA&gl=US"gl=US –

The Krispy Kreme® app is filled with tons of delightful surprises! Download now to experience the joy of Krispy Kreme and all the exciting features: Mobile Ordering (Place your order for either in-store pickup or delivery; Customize your own box with a dozen of your favorite doughnuts); Krispy Kreme Rewards™ (Sweet Rewards! Earn your way to free doughnuts, dozens, or coffee and receive a free doughnut just for signing up!); Hot Light™ (Find out exactly when hot, fresh doughnuts are coming off the line, Locate the nearest Krispy Kreme shop, wherever you are).

•Participated in and contributed to Agile meetings (e.g., Scrum, Sprint, etc.) with multiple cross-functional teams for getting specific customs SDK definitions.

•Communicated with offshore teams to coordinate work and testing.

•Used and sent tracking data from FusedLocationProvider to the server to track the device during deliveries.

•Conducted troubleshooting of production problems arising from API errors and Low Connectivity and refactored code to address those problems.

•Implemented concurrency design pattern using Kotlin coroutines to simplify code that executed asynchronously.

•Performed technical work using Android Studio with Kotlin codebase and MVVM architecture.

•Programmed new Kotlin modules and migrated existing code into Kotlin.

•Refactored callbacks to suspend Coroutines and performed network requests, JSON parsing, and reading from a database.

•Implemented Firebase Cloud Messaging to Push updates to the device and register devices to receive messages from FCM.

•Successfully refactored and enhanced legacy C++ code components within Android apps. This initiative improved code quality, reduced technical debt, and increased code maintainability.

•Worked on service layer that interfaces with CloudOps and Data Team and sanitizing API calls.

•Utilized Retrofit2 and OkHTTP networking libraries to retrieve information relating to status and deliveries.

•Used an Offline-First model using Room Databases and migrate from SQLite implementation.

•Integrated Lottie animation library to parse Adobe After Effects animations exported as JSON and rendering them natively.

•Leveraged GraphQL subscriptions to enable real-time data updates within our Android applications. This allowed users to receive immediate information on promotions, product availability, and store locations, resulting in heightened user engagement.

•Developed custom GraphQL queries tailored to the unique data needs of our Android apps, ensuring a tailored approach to retrieving information while reducing unnecessary data transfers.

•Seamlessly integrated third-party NDK libraries into our Android applications to enhance features and extend capabilities without sacrificing performance.

•Designed and implemented multithreading solutions using the NDK, enabling our apps to efficiently handle concurrent tasks, such as background data processing and real-time updates.

Android Developer September 2017 – December 2019

Victoria’s Secret, Columbus, OH

https://play.google.com/store/apps/details?id=com.victoriassecret.vsaa –

Welcome to the Victoria’s Secret app, your on-the-go destination for the world’s most famous bras, panties, lingerie, sportswear, swimsuits, beauty, accessories and more.

•Integrated Google Analytics to track the usage of application, number of people, number of downloads, etc.

•Utilized Mixpanel and Flurry to generate customized events in the analytics retrieval.

•Utilized Android Studio for IDE.

•Transitioned app from MVP to MVVM architecture.

•Implemented new features in Kotlin and converted some existing Java classes to Kotlin.

•Applied RxKotlin in conjunction with RxAndroid, RxBinding libraries to make app multithreaded and perform synchronous operations.

•Used reactive frameworks such as RxJava, RxAndroid, RxBluetooth, and RxKotlin.

•Managed merge and commits in GitHub.

•Worked in an Agile development environment and applied Scrum processes and Sprints.

•Handled backlog using Jira.

•Supported multiple screen resolutions using different layouts for portrait and landscape.

•Used JUnit, Espresso, and Mockito to complete all test cases.

•Queried for requests utilizing HTTPS SSL and parsed JSON responses.

•Configured a JIRA instance to handle mass ticketing and bug tracking.

•Transitioned use of AsyncTask to do background processing to RxJava with RESTful Web Services managed by Retrofit for better performance.

•Engaged with back-end team to implement electronic payment capabilities.

•Created architecture documentation such as high-level design.

•Designed and implemented complex algorithms to address critical challenges in our Android applications. These algorithms have played a crucial role in achieving specific functionality and improving user experiences.

•Implemented and enforced best practices for NDK development within our Android team, including rigorous code reviews and knowledge sharing sessions.

•Created compound and custom UI components improve the user experience.

Sr. Android Developer January 2016 to September 2017

ADP, Roseland, NJ

https://play.google.com/store/apps/details?id=com.adpmobile.android –

ADP Mobile Solutions provides you with an easy and convenient way to access payroll, time & attendance, benefits, and other vital HR information for you and your team.

•Developed the Android app in both Java and Kotlin using Android Studio.

•Began the shift from Java to Kotlin.

•Used RxJava for most of the asynchronous processes.

•Designed CustomViews to implement UX designs.

•Worked as part of Agile team and contributed in Scrums and Sprints.

•Integrated Java Guava Libraries for string processing, concurrency libraries, and I/O functions.

•Implemented List View using the view Holder pattern to improve the performance.

•Utilized Implicit and Explicit Intents.

•Created custom views to present data as needed.

•Used Shared preferences. Created small testing instances with Android Wear and Android Auto.

•Generated the application with a Model View Presenter architecture.

•Added animations and transitions with out-of-the-box features and third-party libraries.

•Improved search navigation Activity to find out station names.

•Improved layout rendering by saving and optimizing the view hierarchy in all the resources.

•Served as owner of the central Git repository for our team.

•Managed code review sessions to always have high quality (reusable, simple, documented) code.

•Managed the build creation with a Jenkins instance hosted on a private server.

•Created the database using SQLite local file and a Firebase implementation.

•Executed test cases and fixed bugs. Performed automated testing using Robolectric.

•Used the Parcelable interface to serialize the objects.

•Eliminated the use of external libraries by consolidating the use of OKHTTP and GSON.

Android Developer October 2014 – December 2015

American Airlines, Fort Worth, TX

https://play.google.com/store/apps/details?id=com.aa.android HYPERLINK "https://play.google.com/store/apps/details?id=com.aa.android&hl=en_CA&gl=US"& HYPERLINK "https://play.google.com/store/apps/details?id=com.aa.android&hl=en_CA&gl=US"hl=en_CA HYPERLINK "https://play.google.com/store/apps/details?id=com.aa.android&hl=en_CA&gl=US"& HYPERLINK "https://play.google.com/store/apps/details?id=com.aa.android&hl=en_CA&gl=US"gl=US - With the American Airlines app, you’re covered with the information you need exactly when you need it. Need a mobile boarding pass? Wondering where the closest Admirals Club® lounge is located? All of this info, and more, is available at your fingertips.

•Worked in an Agile development environment with peer engineers on a daily basis to scope, develop and deliver a software experience that realizes the product strategy.

•Gathered and documented client requirements and managed client expectations.

•Planned and conducted code reviews and refactoring activities following best practices.

•Worked closely with back-end team to redesign RESTful web services.

•Created a Push Notification Server using NodeJS and implemented MongoDB and MSSQL databases to store unique device keys.

•Worked around BluetoothAAdapters and BluetoothServices with BroadcastRecivers, EventBus and IBinder interface .

•Designed application workflow and wireframe for new modules.

•Improved the performance on the UI by implementing Fragments and RecyclerView.

•Improved the user experience by including android wear compatibility

•Worked closely with designers to create the look and feel of the application meeting Google’s design standards while following company’s corporate identity guidelines.

•Integrated Facebook and Twitter for social networking.

•Designed and implemented a module for users to review their historic travel information.

•Utilized Git version control tool as the source control management system.

•Followed Test-Driven-Development (TDD) and used Mockito PowerMock and Espresso for our default testing frameworks.

•Utilized Jenkins for continuous integration.

Android Application Software Developer August 2013 – October 2014

Epocrates, Austin, TX

https://play.google.com/store/apps/details?id=com.epocrates - Use the Epocrates app to save time in the prescribing moment. The app provides Rx and OTC monographs; prescribing and safety information; adult and pediatric dosing information; adverse reactions, contraindications, black box warnings, pregnancy and lactation considerations, drug interaction checker: generic, OTC, or alternative drugs; pill identifier: and more.

•Built customizable Home screen with drag-and-drop simplicity.

•Pair programmed with senior developer to write TDD testcases for Pill identifier feature using JUnit.

•Utilized Fragments and Tabs to ensure that the UI was compliant with the Android design guidelines.

•Introduced Material Design to the app to provide a more lightweight and standard user interface.

•Created new screens (new splash screen, new usage remaining calculator with custom wave animations) using Custom and Compound View principles.

•Managed multiple callback scenarios for the integration of a new payment method trough a third-party app.

•Worked on "Pull Down To Refresh" functionality to manually refresh the data and cache locally in SQLite database.

•Utilized Circle CI for continuous integration

•Implemented Social Login through Facebook/Google/Twitter SDK.

Android Engineer August 2012 – August 2013

Pocket by Read it Later, San Francisco, CA

https://play.google.com/store/apps/details?id=com.ideashower.readitlater.pro - Use Pocket to capture the content that comes at you all day long, and curate your own space filled with only the topics you care about. Save the latest stories, articles, news, sports and videos from any device, and any publisher or app.

•Used navigation drawer to provide quick and easy access to the menu items.

•Worked with GSON and Jackson library to parse JSON files.

•Used Butter Knife library to apply binding in Android views.

•Built and delivered a highly scalable and maintainable application.

•Introduced the Push Notifications through Urban Airship.

•Created a module based on an Event-driven library (Event Bus) to communicate multiple components in the app efficiently.

•Made use of Bluetooth Low Energy to make tests and handle geo-fencing when getting close to iBeacon devices.

•Collaborated with Software Engineers for the design and development of back-end services.

•Applied RESTful API and data formats like (JSON, XML, etc.).

•Integrated Crashlytics to analyze the behavior of the users.

•Worked with ZXing library for the coupon bar code reading module.

•Implemented the user interface by using Custom Views, ListView, Relative Layout, Linear

•Layout and Table Layout.

Education

Bachelor of Chemical Engineering – Universidad Regiomontana

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